Alzheimer's disease (AD) is associated with marked atrophy of the cerebral cortex and accumulation of amyloid plaques and neurofibrillary tangles. Amyloid plaques are formed by oligomers of amyloid-β (Aβ) in the brain, with a length of 42 and 40 amino acids. α-secretase cleaves amyloid-β protein precursor (AβPP) producing the membrane-bound fragment CTFα and the soluble fragment sAβPPα with neuroprotective activity; β-secretase produces membrane-bound fragment CTFβ and a soluble fragment sAβPPβ.
View Article and Find Full Text PDFRecently, the need of improvement of energy storage has led to the development of Lithium batteries with porous materials as electrodes. Porous Germanium (pGe) has shown promise for the development of new generation Li-ion batteries due to its excellent electronic, and chemical properties, however, the effect of lithium in its properties has not been studied extensively. In this contribution, the effect of surface and interstitial Li on the electronic properties of pGe was studied using a first-principles density functional theory scheme.
View Article and Find Full Text PDFThe half-metallic behavior of the perovskite SrFeMoO (SFMO) suggests that this material could be used in spintronic applications. Indeed, SFMO could be an attractive material for multiple applications due to the possibility that its electronic properties could be changed by modifying its spatial confinement or the relative contents of its constituent transition metals. However, there are no reports of theoretical studies on the properties of confined SFMOs with different transition metal contents.
View Article and Find Full Text PDFIn this work, we address the effects of molecular doping on the electronic properties of fluorinated and chlorinated silicon nanowires (SiNWs), in comparison with those corresponding to hydrogen-passivated SiNWs. Adsorption of n-type dopant molecules on hydrogenated and halogenated SiNWs and their chemisorption energies, formation energies, and electronic band gap are studied by using density functional theory calculations. The results show that there are considerable charge transfers and strong covalent interactions between the dopant molecules and the SiNWs.
View Article and Find Full Text PDFIn the last few decades, there was a marked increase in consumer debt in the United States, Latin America and other emerging countries, spurring a debate about the real costs and benefits of household credit. Using a unique longitudinal dataset with detailed health and balance sheet information from a large sample of 10,900 Chilean households we study the relationship between debt trajectories in a three-year time window and mental health. We find that depressive symptoms are higher for those who have been persistently over-indebted, followed by those who transit from moderate to high debt levels.
View Article and Find Full Text PDFPurpose: The purpose of the study was to examine the association between income inequality and school violence and between the performance inequality and school violence in two international samples.
Methods: The study used data from Trends in International Mathematics and Science Study 2011 and from the Central Intelligence Agency of United States which combined information about academic performance and students' victimization (physical and social) for 269,456 fourth-grade students and 261,747 eighth-grade students, with gross domestic product and income inequality data in 52 countries. Ecological correlations tested associations between income inequality and victimization and between school performance inequality and victimization among countries.
: The possibility that an adsorbed molecule could provide shallow electronic states that could be thermally excited has received less attention than substitutional impurities and could potentially have a high impact in the doping of silicon nanowires (SiNWs). We show that molecular-based ex-situ doping, where NH3 is adsorbed at the sidewall of the SiNW, can be an alternative path to n-type doping. By means of first-principle electronic structure calculations, we show that NH3 is a shallow donor regardless of the growth orientation of the SiNWs.
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